The present invention relates to a hydrostatic release device, that is a device which will respond to a change in ambient pressure to free a release member or link. A particular use of such a device is to release life-saving equipment carried on a ship or aircraft when the ship sinks or the aircraft ditches in the sea. As the ship or aircraft sinks, there will be a change in ambient pressure due to the entry into the water and at a certain predetermined depth the device will respond by releasing equipment.
The equipment may, for instance, comprise a dinghy or an emergency beacon or a radio signalling buoy which may include position signal indicators, etc. The nature of the equipment is not of great relevance to the present invention.
Hydrostatic release devices as such are known but these are generally complex and/or expensive. The present invention therefore seeks to provide an inexpensive release device with few moving parts which will be reliable and trouble-free in use. This is particularly important in the context of an item of safety equipment which will generally only be used once with little or no opportunity for testing.